Vehicular systems for determining whether a vehicle is being held within a road lane and, if not, providing a warning to the driver (lane departure warning) are being developed as part of current vehicle safety equipment.
Sensors for use with lane departure warning (LDW) systems may include cameras mounted within the vehicle compartment, typically between the center rearview mirror and the windshield. From this location, the camera is positioned so that its field of view is directed toward the road in front of the vehicle. The space between the camera and the windshield may be protected by a glare shield to prevent light from outside of the field of view of the camera from interfering with the camera sensing.
The image signals obtained from the camera for the LDW are critical to determining the location of the lane lines and thus the relative location of the vehicle. These image signals may be degraded by frost, ice, or fog on the windshield.